Question 1

If the ratio of parent to daughter isotopes is 25:75, how many half-lives have passed?

Accepted Answer

A)  2
B)  3
C)  1
D)  4E) B) and C)
F) B) and D)

Question 2

A basaltic lava flow contains fragments of sedimentary rocks. Which of the following statements is true regarding their relative ages?

Accepted Answer

A)  The lava flow is younger than the sedimentary rock.
B)  The lava flow is older than the sedimentaryrock.
C)  The lava flow and the sedimentary rock are the same age.
D)  More information would be needed to determine their relative ages.E) A) and B)
F) C) and D)

Question 3

What is the parent-to-daughter isotope ratio if 1 half-life has passed?

Accepted Answer

A)  16:0
B)  8:8
C)  4:12
D)  2:14E) A) and D)
F) All of the above

Question 4

Two layers of rock contain trilobites that have the same body morphology; however, one rock layer is a shale and the other is an ironstone. Can these two layers be used for correlation?

Accepted Answer

A)  No, layers with the same lithology can only be used for correlation purposes.
B)  No, the ironstone has been altered by oxidation and thus is older than the shale.
C)  Yes, if the trilobites are the same, then the layers were formed at the same time.
D)  Yes, the ironstone is the altered remains of the shale and thus the layers are the same.E) A) and C)
F) None of the above

Question 5

Discuss what the numerical age represents when radiometrically dating a basalt, a gneiss, and a quartz sandstone.

Accepted Answer

The numerical age of a basalt gives the ...

Question 6

How much of a radioactive parent isotope will remain after 3 half-lives have passed?

Accepted Answer

A)  one-third
B)  three-halves
C)  one-eighth
D)  one-sixthE) A) and B)
F) All of the above

Question 7

Which of the units in the following image would be least useful for obtaining a numerical age?

Accepted Answer

A)  A
B)  B
C)  C
D)  DE) B) and C)
F) A) and B)

Question 8

The closure temperature represents the point when

Accepted Answer

A)  a magma cools to the point where minerals begin to crystallize.
B)  radioactive isotopes begin to decay.
C)  isotopes are no longer free to move out of a crystal lattice.
D)  the last remaining magma crystallizes.E) A) and B)
F) All of the above

Question 9

A __________ is a geologic layer that is distinct enough to allow it to be found regionally and used to correlate rocks.

Accepted Answer

A)  marker bed
B)  geologic contact
C)  stratigraphic bed
D)  disconformityE) A) and B)
F) B) and C)

Question 10

Why have no rocks older than 4.12 Ga been found in Earth's crust?

Accepted Answer

Rocks older than 4.12 Ga were ...

Question 11

In the following image of the Grand Canyon, identify the angular unconformity.

Accepted Answer

A)  A
B)  B
C)  C
D)  DE) B) and C)
F) C) and D)

Question 12

Sedimentary rocks cannot be used to determine dates on the geologic time scale because the numerical age

Accepted Answer

A)  is the time that the rocks were exposed at the surface.
B)  retains too much error associated with diagenesis.
C)  is the age of the igneous rocks that make up the sediment.
D)  is reset when the sediments are buried and cemented.E) A) and B)
F) A) and C)

Question 13

How is a relative age different from a numerical age? How are each of these determined?

Accepted Answer

A relative age compares the age of one g...

Question 14

Within the world's sedimentary rocks, fossils

Accepted Answer

A)  are rarely, if ever, found.
B)  are randomly distributed.
C)  occur in an ordered sequence.
D)  are found only in igneous rocks.E) None of the above
F) A) and B)

Question 15

If an igneous dike cuts across a sequence of sedimentary beds,

Accepted Answer

A)  the beds must be older.
B)  the dike must be older.
C)  the beds and the dike must have formed at the same time.
D)  their relative ages cannot be determined from the information given.E) C) and D)
F) All of the above

Question 16

A tilted sequence of sedimentary rocks violates which principle?

Accepted Answer

A)  superposition
B)  original continuity
C)  original horizontality
D)  uniformitarianismE) A) and B)
F) A) and C)

Question 17

If horizontal sedimentary strata overlie tilted strata (and no fault is present) , the eroded surface between the horizontal and tilted strata must be a(n)

Accepted Answer

A)  conformable sedimentary contact.
B)  angular unconformity.
C)  disconformity.
D)  nonconformity.E) A) and C)
F) None of the above

Question 18

Correlate the layers in the following three stratigraphic columns by drawing lines from the top and bottom of matching formations. What is the oldest unit in this region? The youngest unit?

Accepted Answer

See the answer below. The olde...

Question 19

An erosional surface between two sequences of flat-lying sedimentary rocks is called a(n)

Accepted Answer

A)  angular unconformity.
B)  disconformity.
C)  nonconformity.
D)  misconformity.E) B) and D)
F) A) and B)

Exam 9: Deep Time: How Old Is Old

Why have no rocks older than 4.12 Ga been found in Earth's crust?

Correct Answer
verified
Rocks older than 4.12 Ga were ...
View Answer

Sedimentary rocks cannot be used to determine dates on the geologic time scale because the numerical age

Correct Answer
verified

Two layers of rock contain trilobites that have the same body morphology; however, one rock layer is a shale and the other is an ironstone. Can these two layers be used for correlation?

Correct Answer
verified

Which of the units in the following image would be least useful for obtaining a numerical age?

Correct Answer
verified

If horizontal sedimentary strata overlie tilted strata (and no fault is present) , the eroded surface between the horizontal and tilted strata must be a(n)

Correct Answer
verified

A tilted sequence of sedimentary rocks violates which principle?

Correct Answer
verified

If an igneous dike cuts across a sequence of sedimentary beds,

Correct Answer
verified

How is a relative age different from a numerical age? How are each of these determined?

Correct Answer
verified
A relative age compares the age of one g...
View Answer

A __________ is a geologic layer that is distinct enough to allow it to be found regionally and used to correlate rocks.

Correct Answer
verified

The closure temperature represents the point when

Correct Answer
verified

Within the world's sedimentary rocks, fossils

Correct Answer
verified

Discuss what the numerical age represents when radiometrically dating a basalt, a gneiss, and a quartz sandstone.

Correct Answer
verified
The numerical age of a basalt gives the ...
View Answer

An erosional surface between two sequences of flat-lying sedimentary rocks is called a(n)

Correct Answer
verified

A basaltic lava flow contains fragments of sedimentary rocks. Which of the following statements is true regarding their relative ages?

Correct Answer
verified

In the following image of the Grand Canyon, identify the angular unconformity.

Correct Answer
verified

Correlate the layers in the following three stratigraphic columns by drawing lines from the top and bottom of matching formations. What is the oldest unit in this region? The youngest unit?

Correct Answer
verified
See the answer below. The olde...
View Answer

What is the parent-to-daughter isotope ratio if 1 half-life has passed?

Correct Answer
verified

If the ratio of parent to daughter isotopes is 25:75, how many half-lives have passed?

Correct Answer
verified

How much of a radioactive parent isotope will remain after 3 half-lives have passed?

Correct Answer
verified

Exam 9: Deep Time: How Old Is Old

Why have no rocks older than 4.12 Ga been found in Earth's crust?

Correct AnswerverifiedRocks older than 4.12 Ga were ...View AnswerShow Answer

Sedimentary rocks cannot be used to determine dates on the geologic time scale because the numerical age

Correct AnswerverifiedShow Answer

Two layers of rock contain trilobites that have the same body morphology; however, one rock layer is a shale and the other is an ironstone. Can these two layers be used for correlation?

Correct AnswerverifiedShow Answer

Which of the units in the following image would be least useful for obtaining a numerical age?

Correct AnswerverifiedShow Answer

If horizontal sedimentary strata overlie tilted strata (and no fault is present) , the eroded surface between the horizontal and tilted strata must be a(n)

Correct AnswerverifiedShow Answer

A tilted sequence of sedimentary rocks violates which principle?

Correct AnswerverifiedShow Answer

If an igneous dike cuts across a sequence of sedimentary beds,

Correct AnswerverifiedShow Answer

How is a relative age different from a numerical age? How are each of these determined?

Correct AnswerverifiedA relative age compares the age of one g...View AnswerShow Answer

A __________ is a geologic layer that is distinct enough to allow it to be found regionally and used to correlate rocks.

Correct AnswerverifiedShow Answer

The closure temperature represents the point when

Correct AnswerverifiedShow Answer

Within the world's sedimentary rocks, fossils

Correct AnswerverifiedShow Answer

Discuss what the numerical age represents when radiometrically dating a basalt, a gneiss, and a quartz sandstone.

Correct AnswerverifiedThe numerical age of a basalt gives the ...View AnswerShow Answer

An erosional surface between two sequences of flat-lying sedimentary rocks is called a(n)

Correct AnswerverifiedShow Answer

A basaltic lava flow contains fragments of sedimentary rocks. Which of the following statements is true regarding their relative ages?

Correct AnswerverifiedShow Answer

In the following image of the Grand Canyon, identify the angular unconformity.

Correct AnswerverifiedShow Answer

Correlate the layers in the following three stratigraphic columns by drawing lines from the top and bottom of matching formations. What is the oldest unit in this region? The youngest unit?

Correct AnswerverifiedSee the answer below. The olde...View AnswerShow Answer

What is the parent-to-daughter isotope ratio if 1 half-life has passed?

Correct AnswerverifiedShow Answer

If the ratio of parent to daughter isotopes is 25:75, how many half-lives have passed?

Correct AnswerverifiedShow Answer

How much of a radioactive parent isotope will remain after 3 half-lives have passed?

Correct AnswerverifiedShow Answer

Correct Answer
verified
Rocks older than 4.12 Ga were ...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
A relative age compares the age of one g...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
The numerical age of a basalt gives the ...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
See the answer below. The olde...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified